`npm publish`'s default was to tag the package we published with
`latest` tag. The NPM ecosystem has expected semantics around this
tag (it uses it by default if you don't pass a version).
From the NPM Docs:
> Typically, projects only use the latest tag for stable release
> versions, and use other tags for unstable versions such as
> prereleases.
We were not doing this, but now we will. We'll have a new tag `dev`
which is the latest build out of CI, and we'll tag builds without a
pre-release tag with "latest".
This change uses virtualenv to insulate us from platform differences
in our building of the Python SDK, and to create an isolated Python 2
environment. This includes meaning we don't need to worry about the
specific location and behavior of Pylint. I *think* this will work
no matter whether it's Mac, Ubuntu, ArchLinux, Windows, and so on.
We do install to the --user directory in the install target using
`pip install -e`, however, which enables the machine-wide symlinking
that we need to support various workflows.
This fixespulumi/pulumi#1007.
While it's safe to publish the tgz that we use internally for other
repositories that are on "the link plan" after the build completes, we
shouldn't publish packages to NPM and PyPi at that point. There are
two reasons for doing this:
1. Publishing packages before they are tested, which means we could
end up publishing packages that don't work.
2. NPM prevents publishing the same package more than once, so if we
had to re-run the job (due to tests failing for transient issues), the
publish step will start failing, preventing us from running the tests
at all.
